# Relationship history for MSHA mine 0800980

Current hierarchy: **Lafarge S A → Midland Chemical Inc → Oak Ridge Mine**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **operator_operates_mine:** Midland Chemical Corp → Oak Ridge Mine; 1981-04-01 to 1982-06-30; source msha-controller-operator-history
- **controller_controls_mine:** C B  Maddox Jr → Oak Ridge Mine; 1981-04-01 to 1982-06-30; source msha-controller-operator-history
- **controller_controls_operator:** C B  Maddox Jr → Midland Chemical Corp; 1981-04-01 to 1982-06-30; source msha-controller-operator-history
- **operator_operates_mine:** Midland Chemical Inc → Oak Ridge Mine; 1982-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Lafarge S A → Oak Ridge Mine; 1982-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Lafarge S A → Midland Chemical Inc; 1982-07-01 to current/open; source msha-controller-operator-history